1. Field of the Invention
The invention relates to nursing implements from which an infant or other suckling animal takes sustenance. In particular, the invention relates to improvements in such implementation so as to permit the ready flow of air into the nursing container as liquid is drawn therefrom by an infant or suckling animal.
2. Prior Art
When an infant or animal suckles at a bottle to draw liquid therefrom through a nipple, the withdrawal of liquid produces a partial vacuum within the nursing bottle. As the vacuum builds up within the nursing bottle, it becomes extremely difficult for the suckling to draw liquid from the bottle.
This phenomenon is well known to parents of infants that draw sustenance by nursing at a baby bottle. As the baby nurses and draws liquid from the bottle, the partial vacuum is created and the nipple collapses because of the differential air pressure within and without the bottle. When the nipple is removed from the infant's mouth and the bottle rotated to an upright position, a squeal of air entering the bottle through the nipple can be heard. This squeal is often thought to be created by air entering the small opening in the nipple through which liquid is drawn. In fact, once the nipple has collapsed, very little, if any, air can be drawn into the nursing bottle through the nursing opening in the nipple. Rather, the manufacturers of nursing nipples have provided one or more fine holes in the base of the nipple through which air enters into the nursing bottle.
These air vent openings, the fine holes at the base of the nipple, are so narrow in diameter they appear to have been made by puncturing the nipple base with a needle. While they function well to permit air to flow into the bottle, while the bottle is in an upright position, they seldom function as an air vent when liquid within the bottle covers these openings, as is the case when the baby is nursing.
If the air venting holes at the base of the nipple are enlarged, air will vent there through while the baby is nursing. However, the manipulation of the nipple by the sucking action of the child causes liquid to be expelled through these enlarged openings in the base of the nipple and the overall functioning of the nursing system is significantly degraded.
Because a simple enlargement of the air vent openings in the base of the nipple proves unsatisfactory in practice, many persons skilled in the prior art have thought to incorporate check valves at the base of the nursing bottle or other nursing liquid container. Unfortunately, check valves eventually provide a source of contamination of the liquids placed within the bottle.
It is an object of the present invention to provide air venting of a nursing liquid container in a manner which utilizes the existing fine venting holes in the base of the nipple already provided by the nipple manufacturer. It is the intent of the present invention to provide means whereby liquid within the container does not come in contact with these fine vent openings in the nipple while the nipple is being suckled, yet air enters through these fine openings to bubble through the liquid and prevent the build up of a partial vacuum within the nursing container.